A coda wave interferometry to characterize and evaluate the powder debonding damage of solid propellant: Experimental investigation and discrete element simulation

Abstract

The debonding of solid filler powder and binder matrix is the main form of damage for composite solid propellant. This study proposes a coda wave interference (CWI) analysis method to quantitatively characterize and evaluate the internal powder debonding damage of composite solid propellant by experiment and discrete element simulation. In order to verify the validity of numerical simulation, the discrete element method (DEM) samples to simulate the powder debonding damage of solid propellant are established, and the DEM simulation and micro-CT scanning experiment are carried out. The micro-experimental and DEM results prove the efficiency and accuracy of DEM samples in modeling the damage behaviors of solid propellant specimens. Furthermore, in order to quantitatively characterize and evaluate powder debonding damage of solid propellant, using CWI method to analyze the damage states of solid propellants in the experiment and DEM simulation of tension. Two coda evaluation parameters based on different damage states are proposed, and the relationship curves of coda evaluation parameters and tensile strain are obtained. Though the analysis of the curve results of experiment and DEM simulation, the validity of CWI is demonstrated. The coda evaluation parameters can quantitatively identify and judge the accumulation process of initial damage, the appearance of micro holes and the failure point of propellant.